So the extra save here (over the UUID) was to try and preserve some sort of human-readable format for the group name in the Django admin area.  I'm not sure that it matters, but when I saw the UUID strings there, I thought it might be useful to transform back to some semblance of the original name.  The ID prefix is to avoid running into the unique constraint, and as you noted, to signify that the group is part of the enhanced model.  Groups created outside of this workflow would not have the prefix.